Artificial Intelligence in Cardiology: An Australian Perspective.

Significant advances have been made in artificial intelligence technology in recent years. Many health care applications have been investigated to assist clinicians and the technology is close to being integrated into routine clinical practice. The high prevalence of cardiac disease in Australia places overwhelming demands on the existing health care system, challenging its capacity to provide quality patient care. Artificial intelligence has emerged as a promising solution. This discussion paper provides an Australian perspective on the current state of artificial intelligence in cardiology, including the benefits and challenges of implementation. This paper highlights some current artificial intelligence applications in cardiology, while also detailing challenges such as data privacy, ethical considerations, and integration within existing health infrastructures. Overall, this paper aims to provide insights into the potential benefits of artificial intelligence in cardiology, while also acknowledging the barriers that need to be addressed to ensure safe and effective implementation into an Australian health system.

Contemporary Evidence-Based Diagnosis and Management of Severe Coronary Artery Calcification.

Percutaneous treatment of heavily calcified coronary lesions remains a challenge for interventional cardiologists with increased risk of incomplete lesion preparation, suboptimal stent deployment, procedural complications, and a higher rate of acute and late stent failure. Adequate lesion preparation through calcium modification is crucial in optimising procedural outcomes. Several calcium modification devices and techniques exist, with rotational atherectomy the predominant treatment for severely calcified lesions. Novel technologies such as intravascular lithotripsy are now available and show promise as a less technical and highly effective approach for calcium modification. Emerging evidence also emphasises the value of detailed characterisation of calcification severity and distribution especially with intracoronary imaging for appropriate device selection and individualised treatment strategy. This review aims to provide an overview of the non-invasive and invasive evaluation of coronary calcification, discuss calcium modification techniques and propose an algorithm for the management of calcified coronary lesions.

Q Fever Endocarditis: A Review of Local and all Reported Cases in the Literature.

BACKGROUND: Q fever endocarditis by Coxiella burnetii is rare and presents a diagnostic challenge. With limited data available, the aim of this study was to review all reported cases together with unpublished local cases to understand risk factor profiles, diagnostic methods, clinical features, treatments and outcomes. METHODS: A search of the PubMed database using the term 'Q fever endocarditis' identified cases between 1950-2019. Included cases had positive polymerase chain reaction testing, valve culture or serology. Separately, to identify local cases meeting our criteria we queried the Western Australian Health Open Patient Administration System at two local hospitals for the ICD-10-AM diagnosis code A78 between 2013-2019. RESULTS: We identified 181 cases from 31 publications and four local cases to create a combined series of 185 cases. The majority 141 (76%) were male and only 11% had normal cardiac valves. Most (72%) of patients had a history of contact with animals or travel. Nearly all (98%) cases had positive serology and over half (56%) had surgery performed. Overall mortality was 17%, and mortality for native valve endocarditis and prosthetic valve endocarditis was 12% and 3% respectively. No patients treated with doxycycline and hydroxychloroquine died. Mortality prior to 1999 was 28%, compared with 5% for more recent cases. CONCLUSION: Serological diagnosis is key in Q fever endocarditis and possible risk factors exist such as male gender, pre-existing valvular conditions and contact with animals or travel. Native valve endocarditis and treatment with drugs other than doxycycline and hydroxychloroquine increase the risk of death.

Ischaemic Stroke and the Echocardiographic "Bubble Study": Are We Screening the Right Patients?

BACKGROUND: Patent foramen ovale (PFO) is a potential mechanism for paradoxical embolism in cryptogenic ischaemic stroke or transient ischaemic attack (TIA). PFO is typically demonstrated with agitated saline ("bubble study", BS) during echocardiography. We hypothesised that the BS is frequently requested in patients that have a readily identifiable cause of stroke, that any PFO detected is likely incidental, and its detection often does not alter management. METHODS: This was a retrospective observational study of patients with recent ischaemic stroke/TIA referred for a BS. Patient demographics, stroke risk factors, vascular/cerebral imaging results and transoesophageal echocardiogram (TOE) reports were recorded. A "modified" Risk of Paradoxical Embolism (RoPE) score was calculated. Change in management was defined as antiplatelet/anticoagulant therapy alteration or referral for PFO closure. Bubble Study complications were recorded. RESULTS: Among 715 patients with ischaemic stroke/TIA referred for a BS, 8.7% had atrial fibrillation and 9.2% had carotid stenosis ≥70%. At least three stroke risk factors were present in 39.3% and only 47.1% of patients screened had a "modified" RoPE score of >5. A PFO was detected in 248 patients of whom only 31% (77/248) had a subsequent change in management. Of BS performed, 1/924 patients (0.1%) suffered a TIA as a complication. CONCLUSIONS: The echocardiographic BS is frequently performed in patients that have a readily identifiable cause of stroke and whose PFO unlikely relates to the stroke/TIA. Bubble Study findings resulted in a change in management in the minority. The procedure is safe but the complication rate warrants informed consent.

Cardiac computed tomography post-transcatheter aortic valve replacement.

Transcatheter aortic valve replacement (TAVR) is performed to treat aortic stenosis and is increasingly being utilised in the low-to-intermediate-risk population. Currently, attention has shifted towards long-term outcomes, complications and lifelong maintenance of the bioprosthesis. Some patients with TAVR in-situ may develop significant coronary artery disease over time requiring invasive coronary angiography, which may be problematic with the TAVR bioprosthesis in close proximity to the coronary ostia. In addition, younger patients may require a second transcatheter heart valve (THV) to 'replace' their in-situ THV because of gradual structural valve degeneration. Implantation of a second THV carries a risk of coronary obstruction, thereby requiring comprehensive pre-procedural planning. Unlike in the pre-TAVR period, cardiac CT angiography in the post-TAVR period is not well established. However, post-TAVR cardiac CT is being increasingly utilised to evaluate mechanisms for structural valve degeneration and complications, including leaflet thrombosis. Post-TAVR CT is also expected to have a significant role in risk-stratifying and planning future invasive procedures including coronary angiography and valve-in-valve interventions. Overall, there is emerging evidence for post-TAVR CT to be eventually incorporated into long-term TAVR monitoring and lifelong planning.

Enhancing Risk Stratification on Coronary Computed Tomography Angiography: The Role of Artificial Intelligence.

PURPOSE: To describe and outline the role of artificial intelligence (AI) in assisting coronary computed tomography angiography (CCTA) in enhancing risk stratification. METHODS: A comprehensive review of the literature was performed to identify published work investigating the utility of applying AI to CCTA. FINDINGS: CCTA is an excellent diagnostic tool for the detection of atherosclerotic cardiovascular disease. The noninvasive nature and high diagnostic accuracy have made CCTA a viable alternative to invasive coronary angiography to detect luminal stenosis. However, it is now understood that stenosis is just one factor that predicts cardiac risk and other factors need to be considered. CCTA-derived plaque biomarkers have since emerged as established predictors of cardiac events to improve risk stratification. Despite awareness of these biomarkers, they are still yet to be incorporated into routine clinical practice. The major barriers to implementation include the specialized skills required for image evaluation and the time intensive nature of analysis. With the many recent advancements in the technology, AI presents itself as a promising solution. AI is attractive because it has the potential to rapidly automate technically challenging tasks with exceptional accuracy. IMPLICATIONS: Developments in the field of AI are occurring at a rapid rate. There is already increasing evidence of the potential AI has to greatly improve the utility of CCTA by improving analysis time and extracting additional prognostic data from new plaque biomarkers. There are, however, technical and ethical challenges that need to be considered before implementing such technology into routine clinical practice.

Short-term DAPT after coronary stenting has similar ischemic and bleeding outcomes as long-term DAPT: a 5-year population-based cohort study.

BACKGROUND: Optimal duration of dual antiplatelet therapy (DAPT) following percutaneous coronary intervention (PCI) remains controversial. AIM: We investigated the relationship between DAPT duration following PCI and long-term ischemic and bleeding outcomes under real-world conditions. METHODS: Patients aged ≥ 65 years who underwent PCI with stenting in Western Australian hospitals between 2003 and 2008 and survived 2 years were identified from linked hospital admissions data. The primary outcome was major adverse cardiovascular and cerebrovascular events (MACCE) defined as a composite of all-cause death and admissions for acute coronary syndrome (ACS), coronary artery revascularization procedure, stroke, and major bleeding. Secondary outcomes were ACS admissions, all-cause death, and major bleeding admissions. Patients were followed up for 5 years from initial PCI. RESULTS: A total of 3963 patients were included in the final analysis. The mean age of the cohort was 74.5 ± 6.1 years with 67.3% males. No significant difference was seen with 6-12, 12-18, or 18-24 months DAPT, compared to 0-6 months DAPT duration for MACCE and all secondary outcomes at 3- and 5-year post-PCI. CONCLUSION: There is no significant difference in both bleeding and ischemic outcomes in long-term DAPT as compared to short-term DAPT for first- and second-generation drug-eluting stents in a real-world population.

Hepatic fat as a novel marker for high-risk coronary atherosclerotic plaque features in familial hypercholesterolaemia.

BACKGROUND & AIMS: Hepatic steatosis has been associated with increased risk of coronary artery disease. Individuals with familial hypercholesterolaemia have accelerated but variable progression of coronary artery disease. We investigated whether hepatic steatosis is associated with novel coronary atherosclerosis biomarkers in adults with heterozygous familial hypercholesterolaemia, using comprehensive coronary computed tomographic angiography. METHODS: We conducted a cross-sectional study of 213 asymptomatic patients with familial hypercholesterolaemia (median age 54.0 years, 59 % female) who underwent coronary computed tomographic angiography for cardiovascular risk assessment in an outpatient clinic. High-risk plaque features, plaque volume and pericoronary adipose tissue attenuation were assessed. From concurrently captured upper abdominal images, severity of hepatic steatosis was computed, as liver minus spleen computed tomography attenuation and stratified into quartiles. RESULTS: Of 213 familial hypercholesterolaemia patients, 59 % had coronary artery calcium, 36 % obstructive coronary artery disease (≥50 % stenosis) and 77 % high-risk plaque features. Increasing hepatic steatosis was associated with higher calcium scores, more high-risk plaque features and presence of obstructive coronary artery disease. Hepatic steatosis was associated with the presence of high-risk plaque features (OR: 1.48; 95 % CI: 1.09-2.00; p = 0.01), particularly in the proximal coronary segments (OR: 1.52; 95 % CI: 1.18-1.96; p = 0.001). Associations persisted on multivariable logistic regression analysis adjusting for cardiometabolic factors, obstructive coronary artery disease and calcium score. Hepatic steatosis was associated with higher plaque volumes (Q4: 499 mm3 vs Q1: 414 mm3, p = 0.02), involving mainly low attenuation and noncalcified plaques (both p = 0.03). No differences in pericoronary adipose tissue attenuation were observed. CONCLUSIONS: Hepatic steatosis is associated with multiple indices of advanced coronary atherosclerosis in familial hypercholesterolaemia patients, particularly high-risk plaque features, independent of conventional cardiovascular risk factors and markers. This may involve specific mechanisms related to hepatic steatosis. CLINICAL TRIAL NUMBER: N/A.

Coronary computed tomographic angiography derived findings and risk score improves the allocation of lipid lowering therapy compared to clinical score.

ABSTRACT: The initiation of therapy for atherosclerotic cardiovascular disease (ASVCD) is currently guided by cohort-based risk scores. Coronary computed tomographic angiography (CCTA) offers more personalised risk assessments to optimise therapy allocation. This study investigates the utility of CCTA determined coronary stenosis (both obstructive and non-obstructive plaque) to guide allocation of lipid lowering therapy. A retrospective analysis of 450 patients with CCTA performed for the assessment of chest pain at a single centre was conducted. Baseline characteristics, investigations, treatments and clinical outcomes were recorded. The allocation of lipid lowering therapy was evaluated with three models, cohort-based risk score (pooled cohort equation), a previously validated CCTA based clinical risk score (pooled cohort equation and CCTA findings) and CCTA alone (without clinical characteristics). The reclassification analysis included 266 patients. Compared to the cohort-based risk score, CCTA based clinical risk score in total reassigned 23% of patients. CCTA alone compared to the CCTA based clinical risk score correctly reassigned 23% and incorrectly reassigned 10%. When comparing the performance of CCTA alone against the cohort-based risk score, both the additive NRI of 25.8 (95% CI 4.12-37.56) and absolute NRI of 13.2 (95% CI 5.88-19.77) was significant. Revascularisation was required in 3% with a low cohort-based risk, but no patients with low risk as per CCTA alone or CCTA based clinical risk score required revascularisation The use of a CCTA based clinical risk score or CCTA alone compared to cohort-based risk scores can improve the allocation of lipid lowering therapy.

The Utility of Circulating and Imaging Biomarkers Alone and in Combination in Heart Failure.

Clinical trials in the treatment of heart failure have relied on the use of a composite of hard clinical endpoints to evaluate the efficacy of the treatment arm. This has led to prolonged trials requiring large patient cohorts and extensive funding to reach statistical significance. In this paper, we have explored the potential of currently available circulating and imaging biomarkers associated with heart failure as a surrogate for hard clinical end points in clinical trials. This would be expected to result in shorter trials, smaller patient cohorts and limited funding required. We have subsequently theorized on combining circulating and imaging biomarkers as a surrogate for clinical end points such as hospitalization from heart failure and cardiac mortality.